#!/usr/bin/perl -w
use strict;

my @days=qw(Sunday Monday Tuesday Wednesday Thursday Friday Saturday);
my(@now, $now, $since_mon);

foreach my $t (0..7)
{
    $now=time+$t*60*60*24;
    @now=localtime($now);
    print showday(@now), ' is ';
    $since_mon=(($now[6]+6)%7)*24 + $now[2];
    $now[6]=(int($since_mon / 28) + 2)%7;
    $now[2]=int($since_mon % 28);
    print showday(@now), "\n";
}

sub showday
{
    my @now=@_;

    my $ret=sprintf '%-10s', $days[$now[6]];
    $ret.=join ':', @now[2,1,0];
    return $ret;
}